Growth of Highly Uniform 2-inch MoS2 Wafers Using Liquid Precursor Spraying

Abstract

With studying elapse, MoS2 has been proofed showing excellent property in electronics and optoelectronics, which promote to fabricate future novel integrated circuits and photodetectors. However, the high-uniform wafer-scale growth is still in its early stage, especially how to control the precursor and its distribution. Herein, we propose a new method, spraying Mo-precursor, which is proofed to fabricate high-uniform 2-inch monolayer MoS2 wafer. The Mo-precursor concentration and spray time are the key parameters which have been systematically studied. The monolayer and bilayer coverage, Raman vibration, PL emission property are investigated. It was found that when the Mo-precursor concentration is 10 mg/mL and spray time is 8 min, the as-grown MoS2 wafer has the highest quality and electrical performance. By study the electrical property of the transistor arrays, it was found that the MoS2 transistors have slight vibration, the average ON/OFF ratio is 1.21×106 and the maximum carrier mobility is 13.39 cm2 V-1 s-1 without further optimizing the device fabrication. These results directly indicate the spray method could fabricate MoS2 wafer with both high optical and electrical uniformity. Moreover, the influence of bilayer coverage on the optical property and electrical property is studied which demonstrates that the additional bilayer nucleation would increase the scattering center and thus suppress the electrical performance. By this method, we have successfully grow more than 100 2-inch wafers with stable process, which further proof its potential application in future MoS2 electronics and integrated circurits.